Relaxation apparatus



K. SC-HLESINGER RELAXATION APPARATUS Dec, 3, 1940.

2 Sheets-Sheet 1 Filed June 7, 1938 bee. 3, 1940.

K.SCHL ESINGER 2,224,116

RELAXATION-APPARATUS v Filed June 7, 193a 2 sheets-sheet 2 "wgmnq Patented Dec. 3, .1940 v UNITED ,STATES RELAXATION APPARATUS Kurt Schlesinger, Berlin, Germany, assignor, by

mesne assignments, to Loewe Radio, Inc., a corporation of New York Application June 7, 1938, Serial No. 212,317 v In Germany June 10, 1937 10 Claims.

Higher demands are continuously being placed on linearity of the deflection of cathode rays in television and oscillograph'design. Particularly in the utilisation of large amplitudes the natural deviations fromithe linearity, caused for example 1 by the curvature of the-tube characteristic, must, therefore, of necessity, make. themselves noticeable in more and more interfering form. In 10 modern television tubes with very short index length, in .which the width of the picture is already approximately equal to the index length of the cathode ray, and angles of deflection of 2 x 20 occur, the end tubesof the relaxation transformer" or the relaxation magnet coil must already be controlled to full extent and it is accordingly impossible any longer to efiect limitation to the middle linear portion of the characteristic, as the anode outputs which would then require to be employed would already come within 9 the order of 20-40watts.

, The applicant has found a method which en- I ables the non-linearity in the lower band of the tube characteristic to be eliminated. The methr 0d operates with the inclusion of tuned self-inductions in the anode circuit of the end stages and utilises the natural oscillation of these selfinductions. The basic features are explained by Figs. 1 and 2.

In Fig. 1, for example, I is the symbol for a relaxation oscillation generator for ideal sawtooth curves. This generator may consist, for example, of a condenser, which is charged by way of a resistance and is discharged by a parallel-connected gas-filled grid-controlled electronic discharge tube.- If with this linear grid potential there is controlled an end tube 2, which is shown to be a pentode, for the purpose of being able to regard the anode circuit as being controlled in non-reactive fashion, and if in the anode circuit there is merely an ohmic resistance-3, the anode alternating potential corresponds to the curve 'as/as in Fig. 2. The curve ascends in linear fashion in the zone 4 up to the relaxation point K, 5 then descends exponentially in the zone 5 corresponding to the discharge of thecon-denser, and includes at point Q a portion which is useless for television purposes and is caused by the curvature of the tube characteristic in the case of negative biasses. As the applicant has found, it is, however, possible by the inclusion of a coil 1 in serieswith the anode resistance 3, which fl0.'resistance 3 is exactly adapted in size, itmay' coil is tuned with its natural periodicity approx-,

be accomplished that the portion be of the potential curve of the coil always lies with equal ascent at the point P against the normal portion at. The portion be is accordingly still capable of being employed for television purposes, and the deflection coordinate thus obtained may provide for up to 50% of'the'total image deflection dependent on the ratio between coil im-. pedance and series resistance 3. There is to be observed as additional advantage upon the connection of suitably selected oscillatory chokes 1 an acceleration of the return portion b5. It

will be clear in the matter of connections that that which is attained in the anode circuit by means of coils can also be accomplished in the grid circuit by other connection elements. An essential feature is the lifting of high frequency in the train of the amplification between relaxation potential generator and relaxation potential consumer.

In Fig. 3 there is shown by way of example the use of the anode oscillatory choke when employing a relaxation transformer. The relaxation transformer 8 taps on the primary side the ;potential '6, which is additively composed of the resistance potential 3 and the oscillatory choke potentiall,in which connection its primary impedance must be fundamentally large as compared with the total maximum impedance of the series connection 3/1. In this case the secondary potential becomes an image of the primary potential, and accordingly is as indiinterference upon the'transformation the secondary winding 812 may iii certain circumstances commence to oscillate with its natural-oscillation, the frequency of which is governed by its self-induction and the associated wire capacities. These natural oscillations can be eliminated entirely by theinclusion of a damping ,cated in Fig. 2., It has been found that as sole the potential portion as without a break in continuity and with constant slope.

In this connection it may be remarked that the adjustment of the transition point can also be influenced by a resistance la in parallel with the choke (Fig. 1). In the most general case series and parallel damping, in accordance with Fig. la, can be merged one into the other with the aid of a potentiometer, in which connection it is certainly always a condition that the natural periodicity of the coil has been correctly tuned at the outset, i. e., made approxi- .mately to coincide with the .expected duration of the return. The potentiometer HI- in Fig. 1a

' would act in such fashion that when the wiper is right at the bottom a relaxation curve results which is purely ohmic, i. e., is distorted in the lower bend, whilst upon location of the wiper.

at the upper end the anode circuit is' substantially purely inductive. In this case there results the differential curve of a sawtooth curve, which is composed solely of impulses and accordingly in turn is also useless for television purposes. The resistance value in the assumed example would amount to approximately 3,000

' Ser. No. 203,487, corresponding to German application B99203) that this auxiliary potential eh must be in amount equal to half the amplitude of ex and in form such that it results in a distinctly positive maximum in the case of both edges of the picture. It has also been disclosed that a curve of this character can be produced from a sawtooth curve by causing'a capacity of suitable size, which is designated H in Fig. 4

' to be charged by a potential source which has itself a sawtooth form. This is shown in Fi 4 in the form of the auxiliary transformer l2. Since only a potential free of direct current can result at the terminals of the condenser I I, it is necessary upon the wide-angle correction to supply to the television tube l0 an auxiliary potential l3 of slight positive value beyond the anode potential, so that the summit of the correction parabola just reaches the anode potential,- which is equivalent to sharp adjustment of the centre of the image.

The point of interest in the present connection is the fact that the phase of the primary potential of the rectifying transformer l2 must be advanced in relation to the current phase of the anode current of 2 when employing the pupinization of the main relaxation circuit by the oscillatory choke 1 according to the invention. As can, be recognized from the time curve in Fig. 2, the commencement of the relaxation curve is apparently displaced towards the left when emplaying the oscillatory choke. In a manner of speaking, therefore, the phase of the relaxation initiation is advanced, and it is accordingly neces sary to advance by the same amount thephase of any rectifying auxiliary potentials, which should run synchronously to the relaxation curve. This is carried out in practice by connecting the condenser M in series with the primary winding of l 2. The amount of the rectifying potential can be adjustedby the shunt l5, and the drop in direct current which would otherwise occur at the resistance l5 amounting to approximately 1,000 ohms can be avoided by a bridging choke' l6, which does not take part itself in the oscillation, and the natural oscillation of which is accordingly much lower than the line period."

To quote figures, in an embodiment complying with the conditions above referred to,

The transformer l2 had 2,000 primary turns with a transformation ratio of 1:3:

The integration condenser had 200 cm., so that the natural oscillation of the secondary winding was of the order of the line period, 1. e., approximately 12,000 cycles.

In these circumstances the phase condenser I4 required to be finely adjusted between 4,000 and 6,000 cm., whilst the primary resistance I5 was of the same order as the main working resistance 3, Via, approximately 1,000 ohms. The gain in potential of 1:2.5 was again consumed in such fashion by the loss of potential upon the integration. i. e., upon the charging of the condenser II, that the said ratio: correction=one-half of deflecting potential was brought about. The auxiliary potential l3 in turn is equal to approximately onethird of'the rectifying potential, i. e., equal to one-sixth of the deflecting potential, which may be directly deduced from calculation of the mean value of the direct current contained in a parabola.

I claim:

1. An arrangement for synchronising a tele vision receiver having a source of synchronising signals, a relaxation oscillation generator, and an amplifier, the input of which being coupled to the output of said generator, the output of which being coupled to the deflection elements of a cathode ray tube, said amplifier being so biassed that at least the nearly complete nonlinear lower part and the linear upper part of the valve characteristic, are used for the amplification, and comprising means for removing the distortion of the amplified oscillations effected by the amplification in the lower non-linear bend of the characteristic.

2. An arrangement for synchronising a television receiver having a source of synchronising signals, a relaxation oscillation generator, and an amplifier, the input of which being coupled to the output of said generator, the output of which being coupled to the deflection elements of a cathode ray tube, said amplifier being so biassed that at least the nearly complete non-linear lower part and the linear upper part of the valve characteristic, are used for the amplification, and comprising means for removing the distortion of the amplified oscillations effected by the amplification in the lower. non-linear bend of the characteristic, said means consisting of a choke being connected in series to the anode-resistance of the amplifier the natural oscillation of which has a frequency corresponding to the return period of least the nearly complete non-linear'lower part and the linear upper part of the valve characteristic, are used for the amplification, and compris ing means for removing the distortion of the amplified oscillations effected by the amplification in the lower non-linear bend of the characteristic, said means consisting of a choke being connected in the anode circuit of the amplifier in series to a variable resistance.

4. An arrangement for synchronising atelevision receiver having a source of synchronising signals, a relaxation oscillation generator, and an amplifier, the input of which being coupled to the output of said generator, the output of which being coupled to the deflection elements of a cathode ray tube, said amplifier being so biassed that at least the nearly complete non-linear lower part and the linear upper part of the valve characteristic', are used for the amplification, and

comprising means for removing the distortion of the amplified oscillations effected by the amplification in the lower non-linear bend of the characteristic, said means consisting of a choke'being connected in the anode circuit of the amplifier in parallel to a variable resistance.

5. An arrangement for synchronising a television receiver having a source of synchronising signals, a relaxation oscillation generator, and an amplifier, the input of which being coupled to the output of said generator, the output of which being coupled to the deflection elements of a cathode ray tube, said amplifier being so biassed that at least the nearly complete non-linear lower part and the linear upper part of the valve characteristic, are used for the amplification, and comprising means for removing the distortion of the amplified oscillations effected by the amplification in the lower non-linear bend ofthe characteristic, said amplifier being a pentode.

.6. An arrangement for synchronising a television receiver having a source of synchronising signals, a relaxation oscillation generator, and an.

amplifier, the input of which being coupled to the output of said generator, the output of which-being coupled to the deflection elements of a cathode .ray tube, said amplifier being so biassed that at least the nearly complete non-linear lower part and the linear upper part of the valve characteristic, are used for the amplification, and comprising means for removing the distortion of the amplified oscillations effected by the amplification in the lower non-linear bend of the characteristic,

the output of said amplifierlbeing coupled to said deflection elements by a transformer, the secondary of which is connected in push-pull to the deflection elements.

, '7. An arrangement for synchronising a television receiver having a source of synchronising signals, a relaxation oscillation generator, and an amplifier, the input of which being coupled to the output of said generator, the output of which being coupled to the deflection elements of a cathode ray tube, said amplifier being so biassed that at least the nearly complete non-linear lower part and the linear'upper part of the valve characteristic, are used for the amplification, and comprising means for removing the distortion of the amplified, oscillations effected-by the amplification in the lower non-linear bend of the characteristic, the output of said amplifier being coupled to said deflection elements by a transformer, the secondary of which is connected in push-pull to the deflection elements, the primary of which has an impedance, being large. as compared with the impedance of the anode resistance comprising said choke, and is connected in parallel to said anode resistance.

8. An arrangement for synchronising a televisionreceiver having a source of synchronising signals, a relaxation oscillation generator, and an amplifier, the input of which being coupled to the output of said generator, the output of which be-' ing coupled to the deflection elements of a cathode ray tube, said amplifier being'so biassed that at least the nearly complete non-linear lower part and the linear upper part of the valve characteristic, are used for the amplification and compris- 'ing means for removing the distortion of the vision receiver having a source of synchronising signals, a relaxation oscillation generator, and an amplifier, the input of which being coupled to the output'of said generator, the output of which being coupled to the deflection elements of a cathode ray tube, said amplifier being so biassed that at least the nearly complete non-linear lower part and the linear upper part of the valve characteristie, are used for the amplification, the output of said amplifier being connected to the primary windings of two transformers, said primary of the first transformer being connected in series to the primary of the second transformer in the anode circuit of said amplifier, the secondary of the first transformer being connected in series to the secondary of-the second transformer in such a manner, that a correction voltage is superposed to the deflection voltage arriving at the deflectionelements, in the primary circuit of the second transformer phase shifting elements being providcd for removing the distortionof the amplified oscillations effected by the amplification in the lower non-linear bend of the characteristic.

.10. An arrangement for synchronising a television receiver having a source of synchronising signals,'.a relaxation oscillation generator, and an amplifier, the input of which being coupled to the output of said generator, the output of which being coupled to the deflection elements of a cathode ray tube, said amplifier being so biassed that at least the nearly complete non-linear lower part and the linear upper part of the'valve characteristic, are used for the amplification, the output of said amplifier being connected to the primary windings of two transformers, said primary of the first transformer being connected in series to the primary of the second transformer inthe anode circuit of said amplifier, the secondary of the first transformer being connected in series to the secondary of the second transformer in such a manner, that a correction voltage is superposed to the deflection voltage arriving at the deflection elements, in the primary circuit of the second transformer phase shifting elements being provided for removing the distortion of the amplified oscillations efiected by'the amplification in the lower non-linear bend of the characteristic as shown in the television image, said phase shifting elements comprising a condenser connected in series to the primary of said second transformer and having such a capacity that said primary circuit oscillates at least about in resonance to the basic period of relaxations oscillation.

'- KURT SCHLESINGER. 

